a Beginning in 1983, a portion
of the fuel tax credited to the Highway Trust Fund is earmarked for transit.

b The tax requirement that
allows for the 10% passenger ticket tax and certain other taxes paid by
airport and airway users to be transferred to the Airport and Airway Trust
Fund expired on Dec. 31, 1995; it was reenacted in August 1996; but expired
again in December 1996.